package org.real.guetshop.aspect;

import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.real.guetshop.annotation.AutoFill;
import org.real.guetshop.constant.AutoFillConstant;
import org.real.guetshop.context.BaseContext;
import org.real.guetshop.enumeration.OperationType;
import org.springframework.stereotype.Component;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.time.LocalDateTime;

@Aspect
@Component
@Slf4j
public class AutoFillAspect {

    /**
     * 定义切入点，它本身不执行任何操作。它的存在是为了与@Pointcut注解关联，提供一个可用的切入点名称
     */
    @Pointcut("execution(* org.real.guetshop.mapper.*.*(..)) && @annotation(org.real.guetshop.annotation.AutoFill)")
    public void autoFillPointCut(){}

    /**
     * 前置通知，在通知中进行公共字段的填充
     */
    @Before("autoFillPointCut()")
    public void autoFillBefore(JoinPoint joinPoint){
        log.info("开始进行公共字段填充......");

        //截取到当前被拦截的方法上的数据库操作类型
        MethodSignature methodSignature = (MethodSignature) joinPoint.getSignature();   //方法签名对象
        AutoFill autoFill = methodSignature.getMethod().getAnnotation(AutoFill.class);  //获得方法上的注解对象
        OperationType operationType = autoFill.value();     //获得数据库操作类型

        //获取到当前被拦截方法的参数--实体对象
        Object[] args = joinPoint.getArgs();
        if (args == null || args.length == 0){
            return;
        }

        Object entity = args[0];

        //准备赋值的数据
        LocalDateTime now = LocalDateTime.now();
        Integer currentId = BaseContext.getCurrentId();

        //根据当前不同的操作类型，为对应的属性通过反射来赋值
        if (operationType == OperationType.INSERT){
            //为4个公共字段赋值
            try {
                Method setCreateUser = entity.getClass().getDeclaredMethod(AutoFillConstant.SET_CREATE_USER
                        ,Integer.class);
                Method setCreateTime = entity.getClass().getDeclaredMethod(AutoFillConstant.SET_CREATE_TIME
                        ,LocalDateTime.class);
                Method setUpdateUser = entity.getClass().getDeclaredMethod(AutoFillConstant.SET_UPDATE_USER
                        ,Integer.class);
                Method setUpdateTime = entity.getClass().getDeclaredMethod(AutoFillConstant.SET_UPDATE_TIME
                        ,LocalDateTime.class);

                //通过反射为对象赋值
                setCreateUser.invoke(entity,currentId);
                setCreateTime.invoke(entity,now);
                setUpdateUser.invoke(entity,currentId);
                setUpdateTime.invoke(entity,now);

            } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
                e.printStackTrace();
            }
        }else if (operationType == OperationType.UPDATE){
            //为两个公共字段赋值
            try {
                Method setUpdateTime = entity.getClass().getDeclaredMethod(AutoFillConstant.SET_UPDATE_TIME,LocalDateTime.class);
                Method setUpdateUser = entity.getClass().getDeclaredMethod(AutoFillConstant.SET_UPDATE_USER,Integer.class);

                //通过反射为对象赋值
                setUpdateUser.invoke(entity,currentId);
                setUpdateTime.invoke(entity,now);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

}
